The use of miniature computers such as personal digital assistants (PDA) and cellular devices capable of text messaging has become increasingly popular. But also portable music players, remote controls, in-car entertainment/information systems and portable electronic games (such as Nintendo's GameBoy or Sony's PlaystationPortable) increasingly utilize text entry functions. Such miniature devices include correspondingly miniature sized input mechanisms. Typically, these devices do not have a full QWERTY-keyboard but only a small set of keys and some software to map multiple key strokes to a conventional letter. The convenience to use such a device crucially depends on the number of keystrokes and hence it is desirable to minimize the number of keystrokes necessary to enter text.
Prior art systems having no letter or character keys and using a rocker move a cursor through a one dimensional (alphabetic) list of letters or through a two dimensional configuration (e.g. mimicking a digit-based phone interface or having arranged the letters in some form of two-dimensional array).
Prior art text input approaches have not sufficiently reduced the number of keystrokes and are only applicable for devices having a keyboard including letter/character keys. Accordingly, what is needed is an improved method for reducing the number of keystrokes necessary to enter text for devices without letter/character keys.